Sea stars (also known as starfish) are in
the class Asteroidea in the phylum Echinodermata, and there are over 2,000
different species worldwide. Like most echinoderms, sea stars generally
have a 5-part symmetry. Most sea stars have 5 arms (or a multiple of 5)
arranged around a central disk, and the mouth is located in the center
of this disk on the underside (called the oral surface). |
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Sea stars move using the many rows of tube
feet on the oral surface of each arm. |
Most sea stars are generalist predators and eat anything they can catch and digest including mussels, clams, snails, barnacles, sea urchins, and even other sea stars. Usually, they evert their stomach out through their mouth and slip their stomach into their prey until the prey is digested. Then the sea star pulls its stomach back in and goes on to the next victim
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When sea stars have access to a lot of food, they can grow very fast and increase in size by many magnitudes
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Last modified September 23, 2005